Rees-Mogg was editor of The Times from 1967 to 1981. He criticised, in a 1967 editorial entitled "Who breaks a butterfly on a wheel?",[7] the severity of the custodial sentence for Mick Jagger on a drugs offence.[8] With colleagues he attempted a buyout of Times Group Newspapers in 1981 in order to stop its sale by the Thomson Organisation to Rupert Murdoch, but was unsuccessful.[9] Murdoch replaced him as editor with Harold Evans. Rees-Mogg wrote a comment column for The Independent from its foundation in the autumn of 1986 until near the end of 1992,[10] when he rejoined The Times[11] where he remained a columnist for The Times until shortly before his death.[12] In his Memoirs, published in 2011, he wrote of Murdoch: "Looking back, he has been an excellent proprietor for the Times, but also for Fleet Street."[13]

He was Chairman of The Zurich Club, "a private, international network of trustworthy and knowledgeable investors and entrepreneurs", and was a regular contributor to a subscription investment advice newsletter, The Fleet Street Letter. Writing in The Times in 2001, Lord Rees-Mogg, who had a house in Somerset, described himself as "a country person who spends most of his time in London", and attempted to define the characteristics of a "country person". He also wrote that Tony Blair was as unpopular in rural England as Mrs Thatcher had been in Scotland. By now his liberal attitude to drugs policy had led to his being mocked as "Mogadon Man" by Private Eye.[8]

The magazine later referred to him as "Mystic Mogg" (a pun on "Mystic Meg", a tabloid astrologer) because of the perception that his economic and political predictions were ultimately found to be inaccurate.[9][15]

In 1964 Rees-Mogg purchased Ston Easton Park near Bath, Somerset, the former home of the Hippisley family. The house had been threatened with demolition and Rees-Mogg partially restored it.[17] He sold the house to the Smedley family in 1978.